import { Platform } from 'react-native';
import * as FileSystem from 'expo-file-system';
import { ProcessingOptions } from '../shared/types/app';

// For actual implementation, you would use:
// import { VideoCompressor } from 'react-native-compressor'; // for React Native
// import FFmpeg from 'react-native-ffmpeg'; // another alternative for more control

/**
 * Video compression utility for optimizing video files across different platforms
 */
export class VideoCompressor {
    /**
     * Compresses a video file to target size or quality
     * 
     * @param sourceUri The URI of the source video file
     * @param options Compression options
     * @returns Promise with the URI of the compressed video
     */
    static async compress(
        sourceUri: string,
        options: {
            targetSize?: number;
            quality?: 'low' | 'medium' | 'high';
            maxDuration?: number;
            maxBitrate?: number;
            outputFormat?: 'mp4' | 'mov';
            includeAudio?: boolean;
        } = {}
    ): Promise<string> {
        // Default options
        const {
            targetSize = 10 * 1024 * 1024, // 10MB
            quality = 'medium',
            maxDuration,
            maxBitrate,
            outputFormat = 'mp4',
            includeAudio = true
        } = options;

        try {
            // Get source file info
            const fileInfo = await FileSystem.getInfoAsync(sourceUri);

            // If file is already smaller than target size, return original
            if (fileInfo.size <= targetSize) {
                console.log('Video already smaller than target size, skipping compression');
                return sourceUri;
            }

            // Determine bitrate target based on quality setting
            const bitrateFactor = quality === 'high' ? 0.7 : quality === 'medium' ? 0.5 : 0.3;

            // Calculate target bitrate based on file size and optional duration
            let targetBitrate: number;
            if (maxDuration) {
                // If we know the duration, we can calculate a more precise bitrate
                // Target size (bytes) * 8 (bits per byte) / duration (seconds) * compression overhead factor
                targetBitrate = Math.floor((targetSize * 8) / maxDuration * 0.8);
            } else {
                // Estimate based on current file size
                targetBitrate = Math.floor((targetSize * 8) / (fileInfo.size / bitrateFactor));
            }

            // Apply ceiling for max bitrate if specified
            if (maxBitrate && targetBitrate > maxBitrate) {
                targetBitrate = maxBitrate;
            }

            // Generate output file path
            const timestamp = new Date().getTime();
            const outputUri = `${FileSystem.cacheDirectory}compressed_${timestamp}.${outputFormat}`;

            // Platform-specific compression implementation
            if (Platform.OS === 'web') {
                return await this.compressVideoWeb(sourceUri, outputUri, targetBitrate, includeAudio);
            } else {
                return await this.compressVideoNative(sourceUri, outputUri, {
                    bitrate: targetBitrate,
                    quality,
                    includeAudio
                });
            }
        } catch (error) {
            console.error('Video compression failed:', error);
            // On error, return the original file
            return sourceUri;
        }
    }

    /**
     * Native platform video compression (iOS/Android)
     * This is a placeholder implementation that would use a native compression library
     */
    private static async compressVideoNative(
        sourceUri: string,
        outputUri: string,
        options: {
            bitrate: number;
            quality: 'low' | 'medium' | 'high';
            includeAudio: boolean;
        }
    ): Promise<string> {
        console.log('Compressing video with options:', options);

        // In actual implementation, this would use a library like react-native-compressor or FFmpeg
        // Example with react-native-compressor:
        /*
        const result = await VideoCompressor.compress(
          sourceUri, 
          {
            compressionMethod: 'auto',
            maxSize: options.bitrate / 8, // Convert bit rate to bytes
            minimumFileSizeForCompress: 0,
            // Map our quality to the library's quality options
            quality: options.quality === 'high' ? VideoCompressor.HIGH 
                    : options.quality === 'medium' ? VideoCompressor.MEDIUM 
                    : VideoCompressor.LOW,
            includeAudio: options.includeAudio,
            removeAudio: !options.includeAudio,
          }
        );
        return result;
        */

        // For now, we'll simulate compression by copying the file
        try {
            await FileSystem.copyAsync({
                from: sourceUri,
                to: outputUri
            });

            return outputUri;
        } catch (error) {
            console.error('Error in simulated compression:', error);
            return sourceUri;
        }
    }

    /**
     * Web platform video compression
     * This is a placeholder implementation that would use WebCodecs or WASM FFmpeg
     */
    private static async compressVideoWeb(
        sourceUri: string,
        outputUri: string,
        targetBitrate: number,
        includeAudio: boolean
    ): Promise<string> {
        console.log('Web compression not fully implemented. Using original video.');

        // In an actual implementation, you would use:
        // - WebCodecs API (modern browsers)
        // - FFmpeg.wasm
        // - Or other web-compatible video processing libraries

        // For now, just return the original video on web
        return sourceUri;
    }

    /**
     * Extracts a thumbnail from a video at a specified position
     * 
     * @param videoUri URI of the video file
     * @param options Options for thumbnail extraction
     * @returns Promise with the URI of the generated thumbnail
     */
    static async extractThumbnail(
        videoUri: string,
        options: {
            quality?: number;
            time?: number; // Position in milliseconds
            format?: 'jpeg' | 'png';
        } = {}
    ): Promise<string> {
        const {
            quality = 0.7,
            time = 0, // Default to first frame
            format = 'jpeg'
        } = options;

        // Generate output file path
        const timestamp = new Date().getTime();
        const outputUri = `${FileSystem.cacheDirectory}thumbnail_${timestamp}.${format}`;

        // In actual implementation, you would use platform-specific methods
        // For React Native:
        /*
        if (Platform.OS === 'ios' || Platform.OS === 'android') {
          // Using a library like react-native-video-processing or FFmpeg
          const result = await createThumbnail({
            url: videoUri,
            timeStamp: time,
            format: format,
            quality: quality
          });
          return result.path;
        }
        */

        console.log('Thumbnail extraction not fully implemented');
        return ''; // Empty string when not implemented
    }

    /**
     * Gets metadata from a video file (duration, dimensions, etc.)
     * 
     * @param videoUri URI of the video file
     * @returns Promise with video metadata
     */
    static async getVideoMetadata(videoUri: string): Promise<{
        duration?: number;
        width?: number;
        height?: number;
        size?: number;
        bitrate?: number;
        rotation?: number;
    }> {
        try {
            // Get basic file info
            const fileInfo = await FileSystem.getInfoAsync(videoUri);

            // In actual implementation, you would use platform-specific methods
            // For example, using FFmpeg or native modules to extract video metadata

            return {
                size: fileInfo.size
                // Other properties would be populated by actual implementation
            };
        } catch (error) {
            console.error('Error getting video metadata:', error);
            return {};
        }
    }
}

/**
 * Video transcoding utility for changing video format or parameters
 */
export class VideoTranscoder {
    /**
     * Transcodes a video file to different format or parameters
     * 
     * @param sourceUri The URI of the source video file
     * @param options Transcoding options
     * @returns Promise with the URI of the transcoded video
     */
    static async transcode(
        sourceUri: string,
        options: {
            outputFormat?: 'mp4' | 'mov' | 'webm';
            resolution?: '480p' | '720p' | '1080p';
            frameRate?: number;
            bitrate?: number;
            includeAudio?: boolean;
            audioBitrate?: number;
        } = {}
    ): Promise<string> {
        const {
            outputFormat = 'mp4',
            resolution = '720p',
            frameRate = 30,
            bitrate = 2000000, // 2 Mbps
            includeAudio = true,
            audioBitrate = 128000 // 128 kbps
        } = options;

        // Generate output file path
        const timestamp = new Date().getTime();
        const outputUri = `${FileSystem.cacheDirectory}transcoded_${timestamp}.${outputFormat}`;

        // In actual implementation, you would use FFmpeg or similar libraries
        console.log('Video transcoding not fully implemented');

        // For now, just copy the file to simulate processing
        try {
            await FileSystem.copyAsync({
                from: sourceUri,
                to: outputUri
            });

            return outputUri;
        } catch (error) {
            console.error('Error in simulated transcoding:', error);
            return sourceUri;
        }
    }
} 